There has been conventionally known a card device that includes mounted therein an authentication unit configured to perform an authentication process with an external device via wired communication and a wireless communication unit configured to perform wireless communication to transmit and receive data.
For performing wireless communication, various electronic circuits are driven, and electromagnetic noise (radio waves) is radiated from such electronic circuits. Accordingly, if wireless communication is performed while an authentication process is being performed, an error may occur in the authentication result under the influence of electromagnetic noise caused with the wireless communication. In particular, since the authentication unit and the wireless communication unit are placed close to each other in a small space of the card device, electromagnetic noise radiated from the wireless communication unit has a significant impact on the authentication process performed by the authentication unit.